The students in general act up in rebellion when Umbridge replaces Dumbledore as the school’s head, but Fred and George’s act of protest – wreaking havoc by setting off a whole crate of their Wildfire Whiz-Bangs fireworks inside the castle – takes the cake. Similarly displeased with Umbridge, the teachers do nothing to try to stop or contain the distracting magical fireworks.

Timeline Notes

All we know is that the day before this occurred was a Monday in April. (OP28)